226 



THE ACTINOMYCETES, Vol. I 



200 



DAYS 



Figure 85. Utilization of galactose bj' S. antibioticus for growth and actinomycin prodviction: 



A A = dry weight of mycelium in mg per 100 ml of medium; X X = percentage of residual 



galactose; O O = actinomycin produced, Mg/n^l of medium (Reproduced by special permission 



from: Katz, E., Pienta, P., and Sivak, A. Appl. Microbiol. 6: 238, 1958). 



strains produce streptomycin, streptocin, cy- 

 cloheximide, and grisein; »S'. fradiae strains 

 produce neomycins and fradicin; S. rimosus 

 produces oxytetracycline and rimocidin. 



2. A single strain of an antibiotic-produc- 

 ing organism may form several chemically 

 related antibiotic substances. This is true of 

 the production of mannosidostreptomycin 

 and streptomycin by S. griseus; of neomycin 



B, and C by S. fradiae; of \iomycin A, B, 

 and C by *S. vinaceus. 



'.i. Organisms producing the .>^ame antibi- 

 otic or closely related compounds are found 

 in different soil regions throughout the world. 

 This is true, for example, of cultures of strep- 

 tomyces producing actinomycin, streptomy- 

 cin, chloramphenicol, the tetracyclines, the 

 erythromj^cins, and others. Since the strains 



